Dynamo-electric machine.



B. PRANKENFIELD. DYNAMO ELECTRIC MACHINE.

. APPLIUATION FILED APB.15,1910

1,023,5 1 1 Patented Apr. 16, 1912.

UM/mm w 5mm a2: QfiucXA UNITED STATES PATENT OFFICE.

BUDD FRANKENFIELD. OF LOS ANGELES. CALIFORNIA, ASSIG OR TO ALLIS-CHALMEBS COMPANYv A CORPORATION OF NEW JER Y.

DYNAMO ELE CTRIC MACHINE.

Specification of Letters Patent.

Patented A r. 16, 1912.

Application filed April 15. 1910. Serial Nth-555,588

To ol/ whom it may con ern lie it known that I. Brno FItAXlH-IXFIELI). a citizen of the United States. residing at lms Angeles. in the county of Los Angeles and State of talit'ornia. have invented certain new and useful improvements in Dynamodfloctrir' achinvs. of which the fol lowing is a lull. clear. and exact specification.

M v invention relates to dynamorlectrir nnu-lrincs.

it has hocn ohservcd that in machines having series windings there is a magnetizing: c i'cot upon the shaft, This effect is due to the fact that the series winding in going from pole to pole makes one or more turns around the shaft. in heavy current machines one such turn 'arrying the full current of the machine produces a very nmrlo-d etl'er-t- Suppose, for instance, that a machine supplies [0.000 amperes; because f this one turn there are then 10,000ampere turns. The resultant magnetization of the shaft is undesirable, particularly at and near the lxwariugs.

It is the object of my present invention to reduce or entirely prevent such magnetization of the shaft. This is accomplished by arranging the series windings and their interconiu-etions so that there is an equal numher ot' ampere turns, as near as may be, around the shaft in each direction, Tn one convenient cmlxuliment of my invention there is an even number of turns around the shaft. the current in one half of these turns circulating around the shaft in one direction and this same current in the other half cireulatin; ar und the shaft in the. opposite direction. lret'crahly there is one turn in each direction.

The various novel features of my invention will appear from the description and drawings. and will he particularly pointed out in the claims.

Figure 1 shows my invention as applied to a compound wound machine provided with series wound ronunutating poles; and, Fig. 2 shows the invention as applied to a compound wound machine without commutating poles.

The machine shown in Fig. l is a four pole machine havin an armature 10,: coinmutator 11, and a tield frame 12 provided with main poles 1.; and eonunutating poles 14. The main poles are provided with shunt I I I t l t t windings l5 and series windings 16. The comiuutating poles 14 are provided with series windings 17. The series circuit extends from the positive hrushcs, through the series windings 16 on the four main poles l3. and the series windings 17 on the several comniutating poles, to the line, thence returnin; to the negative brushes. The conne'ctjons from pole to pole in the main Windings It} extend in a counterclockwise direction around thoshaft 18, whereas the con ucetions from pole to pole of the commutating windings 17 extend from pole to pole in a clockwise direction around the shaft, so that as a result the effects of the two turns around the shaft neutralize each other and no magnetization in the shaft is produced.

In case either the main series winding or the cominutating series winding is shunted, it may be inconvenient to arrange to obtain exact neutralization of the effects produced by the turns around the shaft in he opposite directions. For instance, if the main series winding is shunted. as by a series shunt or by a rhcostat 19, it may sometimes he inconvenient to have the connections for such series shunt or rheostat pass around the shaft in the same direction as does the main series winding which it shunts. It should not however, make a turn around the shaft in the other direction. In that; case the number of ampere turns around the shaft due to one set of interconnections may exceed those clue to the other set of interconnections, butin most cases magnetization to this extent; will not he greatly undesirable. i

Fig. 2 is a six pole machine having an armature 20, a commutator 21, and a field frame 22 provided with .siX tield poles 23, 24, 25, 26, 27, and 28. These [ield poles have shunt field windings "'25) and series field windings 30. The series comm-lions extend from the positive lu'ush in a countcnelorkwise direction around the shaft through the series field coils on the poles l t, 2 and 27 successively, and then in a clockwise direction around the shaft through the series field coils on the poles 28, 26, and 21 successively. The two turns around the shatt. having equal currents in opposite dir ctions. neutr'aliZP each others ett'eets and produce no magnetization in the shaft itselt.

There are many other specific arran mcnts for arrying out my invention t. e

exact arrangement which ie used depending l largely upon the judgment of the designer. The aim is to arrange for an equal number of ampere turns. as nearly as may be, around the shaft in each direction. As stated above, exact equality i, not always conveniently ob tainable. The broad scope of my invention include the idea of neutralizing partly r wholly the ampere turns around the shaft in one direction by ampere turns aroundthe i Shaft in the other direction.

lhe"inventi'on is applicable to all classes of machines having, series windings, whether or not they have shunt windings and whether they are generators or motors. In the following claims: I aim to cover all modifications which do not depart from the spirit and scope of my invention.

- What I claim as new is:

1. In a dynamoelectric machine, a field member having a plurality of main poles and a plurality oioonlmutating poles, series windings onboth of poles, intereonneetions between the series windings on the main poles arranged to carry current around the axis of rotation of the machine in one direction, and interconnections between theseries windings on the commutating poles arranged to carry current: around such axis in the other direction.

2. In a dynainrreleetrie machine, a field member having a plurality of main poles, and a plurality of eomn'iutating poles, series windingson both sets of poles, interconnectione between the series windings on the main poles which with said windings produce a number of ampere turns around the axis of rotation of the machine in one direction, and interoonnectivme between the series windinge on the commutator poles which with said windings produve a number of ampere turns around such axis in the. other direction.

hlilwauliee. ie, Man-h .22, lfllt).

In testimony whereof l atlix nrv .i uature. in the presence of two witnesses.

RUDD FRAXKICNFIELD.

Witnesses:

( E. F1511, J. ll. llaixxa. 

